added default implementation of ModelLoader.newModel(String name, String uri, ASMModel metamodel) calling ModelLoader.newModel(name, metamodel)

Rationale: subclasses that do not take uri into account should not need to implement the specific method that does.
diff --git a/plugins/org.eclipse.m2m.atl.engine.vm/src/org/eclipse/m2m/atl/engine/vm/ModelLoader.java b/plugins/org.eclipse.m2m.atl.engine.vm/src/org/eclipse/m2m/atl/engine/vm/ModelLoader.java
index c1fdf20..38ee432 100644
--- a/plugins/org.eclipse.m2m.atl.engine.vm/src/org/eclipse/m2m/atl/engine/vm/ModelLoader.java
+++ b/plugins/org.eclipse.m2m.atl.engine.vm/src/org/eclipse/m2m/atl/engine/vm/ModelLoader.java
@@ -186,7 +186,9 @@
 	 * @param metamodel
 	 * @return A new ASMModel
 	 */
-	public abstract ASMModel newModel(String name, String uri, ASMModel metamodel);
+	public ASMModel newModel(String name, String uri, ASMModel metamodel) {
+		return newModel(name, metamodel);
+	}
 
 	protected abstract void setParameter(String name, Object value);